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In reply to: bit rate
Hi Gurpreet
Alisth have explained well about your question.I just want to add that run your system with script mode and change data rate in global parameter window.For filter(electrical low pass) ) 0.75*Bit rate is a cut off frequency,you can change it to o.8* bit rate and see the results beacaus for my some of systems it works well.In optiwaves example of CSRZ,MDRZ and DPSK they have considered cut-off frequency 0.8* Bit rate.In reply to: DPSK with optical modulation
I think there have been several discussions on DPSK. You might found any of these links helpful as I don’t have Optisystem on the system I am using currently. Therefor I won’t be able to open the attached file.
https://optiwave.com/forums/search/DPSK/Have a nice time.
Topic: DPSK with optical modulation
Hi,
I am trying to simulate the DPSK transmitter and receiver design with dual electrode MZM. But I am not getting the correct output. kindly help. My BER analyser is not giving any output and my BER test set shows a very high BER value. I am just trying to simulate a DPSK system with MZM modulator (generating Double sideband with carrier signal). Just let me know, if I have any design error in it.
Please find attached my design.
In reply to: Design error
I can’t reproduce the problem you are having with the Direct Detection OFDM sample found in Advanced modulation systems -> OFDM systems.
The BER I get varies with length, and from simulation to simulation. You can reinstall the Samples from the executable found in the installation folder. However, the errors you found will need to be fixed in the next release for the DPSK samples.
In reply to: Design error
Thanks for bringing this to our attention! This file does indeed not work as intended. Luckily the fix is quite simple, just change the Layout parameter Symbol rate to Bit rate/3 or 10.125 MHz. It seems the example files used the default setting of 2.5 Gbps, which is incorrect for this DPSK system. I’ll go through the samples and make sure we fix the ones that need fixing.
In reply to: Design error
I am using Optisuite 13. Let me give you an example of DPSK-pulse generator and decoding. I am not getting the output at the DPSK sequence decoder block. The oscilloscope does not give any output. Besides other design are also not giving the output at the decoding end. The samples which I am using are from optiwave sample 11 folder. I have optisim 13.
Please find attached the screenshot.
Also in OFDM direct detection example, the BER value is always shown 0 irrespective to any change in design such as modulator parameters, fiber length, amplifier gain.Attachments:
Topic: Coherent Optical
In reply to: fabrication of models
NRZ is simple to be implemented so it is widely used for bitrates up to 10G. For higher bitrates more complex modulation formats (DPSK, coherent…) are used because they present less impairments but cost more.
Topic: DPSK-WDM
In reply to: 40 Gb/s DWDM [Optical System]
Please make a 2 channel system of same file “DPSK 7Channels_Script.osd”..two channels transmitted and two received..rest i myself will figure out..thanxx alot
In reply to: 40 Gb/s DWDM [Optical System]
dear Damian..Thanxx alot for ur reply..i got my answers..sorry for bothering you again,have another question..i tried to simulate 40gbps DPSK this time..i used “DPSK 7Channels_Script.osd” and changed the link in it having pre-post compensation and zero dispersion..i am getting max Q factor of 35 at 193.1 THz ( receiver with default figures as in the file “DPSK 7Channels_Script.osd”. Problem is when i change receiver input frequency to some another channel, no eye diagram appears.i am changing “receiver NRZ subsystem” frequency to 193.02..rest everythg remains same at the receiver..can you please suggest the other parameters i have to change to see the eye diagram on some another channel rather than the central channel (193.1 THz)…thankss alot, once again..
regards..In reply to: Cross talk in Polarisation multiplexing
We have many tools for creating polarization multiplexed systems in OptiSystem. The DPSK and QAM transmitters come with a dual polarization variant.
Furthermore, the nonlinear interaction between different polarization states is simulated with a vector model, so phase modulation can be observed. There are even more passive components such as polarization controller’s, waveplates etc.
Regards
In reply to: non linearities
well once again thanxx alot for your reply Damian..i tried alot but dont know how i keep on doing one or the other thing wrong..The self phase modulation box checked/not checked gives me alot of lot of variation in Q factor..i am not sure whether im doing it right and most probably, im doing it wrong ..i will be really really greatful if you can please send me two files..first one having 10 Gbps OOK NRZ or RZ 32 channel WDM system and the second one having 40 Gbps DPSK 32 channel WDM system..further i want to check their Q Factor performance with and without non linear effects…Please help..Thanxx alot..
regards..
maniIn reply to: How to Apply NRZ/RZ coding in DP-QPSK Transmitters
Hi,
You can change these settings in the Optical DPSK transmitter, but not in the QPSK transmitter. However go into the Help document of the DP-QPSK transmitter and take a look at the equivalent layout. You could modulate the optical signal with an additional sine wave to get the RZ format.
Let me know if this works.
In reply to: How Do We Connect BRE Analyzer to a DP-QPSK Reciever
Hi,
Take a look at the sample file found in the “OptiSystem 12 Samples\Advanced modulation systems\PSK systems” folder named “DPSK Step 7 – Transmitter and receiver with eye diagram.osd”. You should be able to take the same approach to observe the eye diagram of a QPSK system.
Generally though since higher order modulation formats have more than 1 bit per symbol the eye diagram is less often used, because there are multiple eyes. Constellation diagrams are probably more useful for visualizing the signal and the error vector magnitude can be calculated from it.
Cheers!
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